1. Field of the Invention
The present invention relates to devices for warming a patient during a medical procedure, and more particularly, to an apparatus for restricting air flow through an inlet port in an inflatable thermal blanket used to warm a patient during a medical procedure.
2. Description of the Related Art
Hypothermia, a condition in which a person's body temperature drops below normal, presents serious potential consequences to a patient. Studies have shown that hypothermia occurs in nearly 75 percent of all patients who undergo surgical procedures. Based on recent numbers, this means that 14 million patients a year in the United States alone suffer from hypothermia during surgical procedures. Hypothermia during surgery may be caused by anesthesia, air conditioning within the operating room, infusion of cold blood, IV solutions, and/or irrigation fluids, in addition to other factors.
One well known method for reducing hypothermia during surgical procedures is to place an inflatable thermal blanket over a patient during a surgical procedure. The thermal blanket is inflated with a warmed airstream, exhausting warmed inflating air onto the patient. An inflatable thermal blanket was first disclosed in U.S. Pat. No. 4,572,188 assigned to Augustine Medical, Inc., the assignee of the present application. U.S. Pat. No. 5,405,371, also assigned to Augustine Medical, Inc., is directed to an inflatable thermal blanket that extends transversely across the arms and chest of a patient's body, and is for use during surgery at or below the patient's chest. These patents disclosed an airstream inlet: In later products, the airstream inlet port comprises a cardboard structure adhesively attached to the surface of the thermal blanket. A hole provided through the inlet port is sized to accept the end or nozzle of an inflation hose. In some thermal blankets, a plurality of inlet ports are provided to allow an inflation hose to be attached at any one of a plurality of locations on the blanket. When an operator inserts the inflation hose into an inlet port, the port is closed about the hose. The surface material of the thermal blanket which coincides with the inlet port is either removed or perforated in order to allow a warmed airstream to pass from the hose through the port to the interior of the thermal blanket. The warmed airstream enters the thermal blanket and is forced out a plurality of small exhaust holes in the lower surface of the thermal blanket. Typically, the user perforates or removes that portion of the thermal blanket which covers an inlet port only when that port is to be used. Accordingly, each of the unused inlet ports remains sealed until after the first use.
One problem with this design is that if the operator decides in the middle of the procedure to move the inflation hose from one inlet port to another, the first port must be resealed or otherwise closed in order to prevent air from exiting through that port instead of through the holes on the lower surface of the blanket, as intended. A number of means have been used to reseal or close an inlet port after removal of an inflation hose. However, none of these means are completely satisfactory. For example, tape has been used to seal an open port, but is generally a nuisance to apply. The prior art suggests many other means and modes for sealing or closing an open port, including: adhesive strips, double sided tape, snaps, zippers, folding flaps, Ziplock®-type seal, hook and loop fastener strips, folding wire, or plastic bars. Each of these methods has a number of drawbacks. The method is either relatively costly, or it is inconvenient, requiring a great deal of attention or time of an operator, possibly during critical moments. Such methods and means require accommodation in manufacture of a thermal blanket, increasing production costs and decreasing manufacturability.
Accordingly, it would be desirable to provide a method and apparatus for closing inlet ports in an inflatable thermal blanket such that the port may be opened and closed conveniently and repeatedly.